﻿<p>The objectified relationship <em>IfcRelAssignsToGroup</em> handles the assignment of object definitions (individual object occurrences as subtypes of <em>IfcObject</em>, and object types as subtypes of <em>IfcTypeObject</em>) to a group (subtypes of <em>IfcGroup</em>).</p>

<p>The relationship handles the assignment of group members to the group object. It allows for grouping arbitrary objects within a group, including other groups. The grouping relationship can be applied in a recursive manner. The resulting group is of type <em>IfcGroup</em>.</p>

<blockquote class="note">
NOTE&nbsp; Examples of groups include zones as a grouping of spaces, distribution systems as a grouping of building service components, or structural analysis models as a grouping of structural items.
</blockquote>

<p>The inherited attribute <em>RelatedObjects</em> gives the references to the objects, which are the elements within the group. The <em>RelatingGroup</em> is the group that comprises all elements. The same object or object type can be included in zero, one or many groups. Grouping relationships are not hierarchical.</p>

<p class="spec-head">Informal Propositions:</p>
<ol>
<li>The group assignment relationship shall be acyclic, that is, a group shall not participate in its own grouping relationship.</li>
</ol>

<blockquote class="history">
HISTORY&nbsp; New entity in IFC1.0. It has been renamed from IfcRelGroups in IFC2x.
</blockquote>